In traditional integrated circuit manufacturing on rigid substrates, passive devices such as capacitors and inductors are typically surface mounted as discrete components via soldering or as embedded integrated devices. These integrated devices can be created from thin films of materials deposited via standard vacuum processes with photolithographic patterning or from thick films which are deposited by screen printing of pastes which are then fired at high temperatures.
These approaches can be unsuitable for manufacturing passive devices on flexible polymer substrates for a number of reasons. For example, the high processing temperatures associated with soldering of discrete components or firing of ceramic pastes could cause significant thermal degradation of the polymer substrate. Additionally, the polymer substrate can undergo a significant amount of dimensional distortion (such as bending and stretching) during handling. This can create challenges in aligning the sequential deposition/subtraction steps during photolithography or other processes.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.